Our 8yo son's WJ-III GE's ranged from 7th to 18th, with an overall score that put him in 13th.
Umm, no. He's not ready for high school... not by a stretch.
I used the GE's on his WJ-III, though, very effectively with the district & school staff. I approached them saying, "Clearly his results don't mean that he should be placed in high school or anything crazy like that... but can we at least agree that the scores suggest he probably shouldn't be in his current (4th grade) classroom?"
The scores were helpful in promoting the discussion about a grade skip, and honestly, after that point, I never brought them up again.
I've enjoyed reading the various debates about the usefulness of IQ & AT testing. Obviously, the scores have opened doors for our son... but after that, I'm starting to fall off the fence to the side of "there's an awful lot of hocus-pocus" in how the results are interpreted, especially when we're dealing with kids at the extremes.